Mailing to Japan for Christmas?

Question:

Hii~
I'm mailing a small flat rate box to Japan via USPS.
Last time I sent a flat rate box to Japan, it only took 4 days >w< (Priority)
But...uhm, since its the holidays, will it affect the amount of days as to when my friend will receive it? D:
Thank you very much!
-Planning to send on December 17-

Answer:

I agree with Homer, mail it ASAP. Christmas may not be a real holiday in Japan, but thousands of people will be sending packages from both countries.